GB743673A - Improvements in or relating to poppet-valve operating mechanism - Google Patents

Abstract

743,673. Valve. gear. ALBION MOTORS, Ltd., and LEE, G. H. April 1, 1954 [April 8,1953], No. 9496/53. Class 7(6) An eccentric bush 3, interposed between a valve rocker 1 and the rocker shaft 5, is urged to rotate by a spring 8 in a direction which moves the rocker to take up any clearance in the valve gear and one of the co-operating cylindrical surfaces of the rocker 1, eccentric 3 or shaft 5 is relieved over a portion extending over less than half its circumference. In Fig. 2 the rocker bore is relieved at B so that when the rocker is rotated by a push rod the relieved part causes the rocker to bind on the eccentric 3 and cause rotation thereof through the remainder of the valve opening period. In Fig. 1 the eccentric 3 of an inlet valve 1 is provided with a projection 6 co-i operating with a slot in a projection 7 of an eccentric 4 on which an adjacent exhaust valve rocker 2 is mounted. When the eccentric 3 is rotated during opening of the inlet valve by the rocker 1, the projection 6 causes rotation of the eccentric 4 against its loading spring 9 to produce clearance in the exhaust valve gear, the clearance being eliminated when the inlet valve is closed by rotation of the eccentric 4 in the opposite direction by the spring 9. Similarly, opening of the exhaust valve by the rocker 2 produces through the projections 7, 6, clearance in the inlet valve gear, which clearance is eliminated by rotation of the eccentric 3 by the spring 8. In a modification the rotation of the eccentrics is derived from a cam. The Provisional Specification describes a clearance adjusting mechanism comprising a wedge member interposed between a cam and a tappet, the wedge being withdrawn when the valve is closed to introduce clearance which clearance is subsequently taken up when the wedge is replaced.